Strip material winder



March 1956 1.. A. TROFlMOV 2,737,354

STRIP MATERIAL WINDER 2 Sheets-Sheet 1 Filed Nov. 29, 1951 1/7 125 /24 57 58 j 64 fi 69 74 76 63 INVENTOR. BY Z61 gpof/mov ATTORNEY United States Patent STRIP MATERIAL WINDER Lev A. Trofimov, Willoughhy, Ohio, assignor to Fairchild Engine and Airplane Corporation, a corporation of Maryland Application November 29, 1951, Serial No. 258,905

3 Claims. (Cl. 242-75) This invention relates to winding apparatus for winding strip material on a drum or the like.

The invention is particularly applicable to unwinding strip material from a coil on a supply drum or the like, and rewinding it in a coil on another drum or the like, and will hereinafter first be described as applied to that use.

There are well known applications for such apparatus in various industrial arts.

Apparatus of this class has been proposed heretofore; but problems have arisen which have not been satisfactorily solved by such prior apparatus.

Among such problems has been that of maintaining a desired tension in the strip being Wound and a desired speed of win-ding, the problem originating in the increasing diameter of the roll as winding goes on.

It is desirable for a single apparatus to be usable to rewind various different kinds of material at ditferent times. Some materials dictate a low speed, whereasothers may advantageously be wound at high speed; and some materials require high tension in the strip being rewound, and such tension in strips of other materials cannot be permitted.

In some prior apparatus of this class, adjustments of strip speed and tension have been proposed, but the provision of adjustments that can be accurately and sensitively made and that will thereafter remain fixed, particularly adjustments of strip tension and speed independently of each other, whereby any desired tension may be had at any desired speed and over wide ranges of tension and speed, has not been satisfactorily accomplished in prior apparatus.

It is an object of the present invention to provide an apparatus of the class referred to which overcomes the foregoing and other objections to prior apparatus.

Another object is to provide a strip winding apparatus having improved means for adjusting the strip speed, and for maintaining it constant.

Another object is to provide a strip winding apparatus having improved means for adjusting the strip tension and for maintaining it constant.

Another object is to provide a strip winding apparatus having improved means for adjusting the speed and tension of strip material being wound, either one alone and independently of the other, or both concurrently.

Another object is to provide improved power means for driving the winding drum of a strip winding apparatus.

Another object-is to provide improved means for tensioning strip material while being Wound.

Another object is to provide improved means for automatically controlling the tension of strip material being wound, responsive to speed of the strip.

Another object is to provide, in a strip winding apparatus, strip speed controlling means comprising improved adjustable speed-reference means.

Another object is to provide, in a strip winding app-aratus of the type in which a rotary device is driven by torque applied to it by the strip on its way to the coil being wound, improved means for controlling the tension in the strip in the parts thereof moving toward and moving from the device.

Another object is to provide improved means for applying compensatin-g torque to the aforesaid rotary device.

With these objects in view, and others that will occur to those skilled in the art which will become apparent hereinafter, the apparatus in an illustrative embodiment of the invention and to be described in detail, comprises, generally speaking, the following parts.

A power unit drives a winding drum to wind strip thereon, drawing it from a supply drum on which it has previously been wound. The power unit has such torquespeed characteristics that if its output speed decreases, its output torque increases, automatically, and vice versa.

Furthermore, the power unit is adjustable so that the value of the output torque corresponding to any "given speed may be increased or decreased.

The torque applied to the winding drum is converted into tangential pull longitudinally of the strip material as it approaches the winding drum. This pull or longitudinal force reacts upon the unwinding drum from which the material is being drawn, and rotates it; and the rotation of the unwinding drum is retarded by a braking apparatus, and it is by this means that torque output of the power unit produces tension in the strip.

Speed responsive apparatus is provided actuated by the speed of the strip to vary the braking action on the winding drum, tending to increase it upon an increas of strip speed and vice versa.

A speed reference unit is provided having a fixed output speed which can be preset and fixed at any desired speed by adjustment. 7

The braking action on the unwinding drum responds jointly to the set constant speed of the speed reference unit and to the speed. of the strip, whereby the strip speed is maintained constant; and the value of the constant strip speed can be selectively adjusted.

With the speed reference unit adjusted for strip speed of some constant value, the output torque of the power unit is adjusted to develop desired tension in the strip. As winding goes on, the diameter of the coil being wound increases. To maintain the given strip speed and tension, the drum must be driven slower and the torque applied to it must be increased. This is provided forby the torque-speed characteristic of the power unit. The drum tends to slow down due to the fixed strip speed and the torque output of the power unit rises.

By adjusting both the speed reference unit and the torque of the power unit, the strip may be wound at any desired speed and tension; high speed and low tension or low speed and high tension or any intermediate values of speed and tension, over a wide range thereof, to adapt the apparatus to requirements of difierent materials.

The adjustment means of the speed reference unit, and that of the power unit are interconnected so that strip can be wound at selected tension at one speed, and then the s eed changed without changing the tension.

The speed responsive apparatus comp-rises rolls driven by the strip drawn therebetween; and in some cases considerable torque is required to drive the rolls. This affects the tension in the strip.

For such cases, an auxiliary power unit is provided applying compensating torque to the rolls of adjustable amount; and the auxiliary power unit, when once adjusted for a desired output torque, maintains that torque constant at all output speeds, whereby, changing the speed of the strip and the rolls, does not disturb the value of the compensating torque applied thereto.

The foregoing description is general, followed herein by a detailed description of a preferred embodiment; the

actual invention being that set forth in the appended claims.

The said preferred embodiment is fully disclosed in the following description taken in connection with the accompanying drawing, in which:

Fig. 1 is a view illustrating the preferred embodiment, somewhat diagrammatically;

Fig. 2 is a view of a part of Fig, 1 illustrating an auxiliary power unit applied thereto;

Fig. 3 is a fragmentary view showing a modification of a braking apparatus of Fig. 1;

Fig. 4 is a fragmentary view of a part of Fig. 1, illustrating a different application of the invention;

The diagrammatic drawing illustrates rotary gears, shafts, etc, but the bearings therefor have been omitted for simplification, and as being known and understood by those skilled in the art.

Referring to Fig. 1, there is shown at 1 a drum, rotably supported on a shaft 2, and having a supply coil 3 of strip material 4 wound thereon; the strip leaving the coil tangentially and going over a cylindrical roll 5 on a shaft 6, then between the roll 5 and a roll 7 on a shaft 8, and between the roll 7 and a roll 9; and therebeyond as shown is being wound in a coil 10 on a winding drum 11.

The roll 9 is supported by or connected to a shaft 12 and the rolls 5, 7 and 9 are maintained in vertical alignment by guides not shown, and are held downwardly by gravity or by spring means indicated at 13 or other suitable well known means, and thereby the strip 4 is gripped between the rolls 5-7 and 79.

By this means when the strip 4 is being wound on the drum 11 and moves linearly through the rolls, it drives the roll 9, and is prevented from slipping thereon,

and thereby drives the shaft 12 always at a rotary speed 1 corresponding to the linear strip speed.

The drum 11 is driven by a shaft 14 which is the output shaft of a power unit indicated generally at A and comprising a power supplying motor 15, running continuously at substantially constant speed; a squirrel cage induction motor as shown being preferred. The power unit comprises also a differential gearing transmission, transmitting motor power to the shaft 14.

The transmission comprises two differential gearings C and D.

The gearing C comprises a spider element 16 rotably supporting pinions 17-17, meshed with two differential gears 18-19.

The gearing D comprises a spider element 20 rotably supporting pinions 21-21 meshed with differential gears 22-23. g

A shaft 24 connects the differential gear 18 to a gear 25; a shaft 26 connects the differential gear 22 to a gear 27; and the two gears 25-27 are meshed with an intermediate gear 28 on the output shaft 14.

The spider element 20 has peripheral teeth meshed with a pinion 29 on the shaft 30 of the motor 15.

The differential gear 19 is connected to a gear 31, and the gear 31 is meshed with another pinion 32 on the motor shaft 30.

At 33 is an electric generator connected to the gear 23, and at 34 an electric motor connected to the spider 16, both preferrably of D. C. type; and they have, respectively, series field windings, 35 and 36; and the generator 33 has a closed local load' circuit comprising wires 37-38, and including, in series in the circuit, the two series field windings 35-36 and the motor 34; and the series field windings have, respectively, rheostats 39-40 for diverting more or less of the generated current there from to adjustably vary the effectiveness thereof; and the field windings 35 and 36 are wound in the direction to cause the generator current to weaken the field of generator 33, and to strengthen the field of the motor 34.

The generator 33 and motor 34 have, respectively, field windings 41 and 42 energized from D. C. mains 43-44,

current from the main 43 flowing to wire 45 and dividing, part flowing through a manually adjustable rheostat 46, through winding 42 to wire 47; and part flowing through a manually adjustable rheostat 48 through winding 41 to wire 47; and the current from wire 47 flowing by wire 49 through a rheostat 50, having a resistor 50A and on by wire 51 through a rheostat 52 to main 44.

The field windings 41-42 are to be considered as producing main or base fields for the generator 33 and motor 34; and can be independently adjusted relatively and manually by the rheostats 48-46, and at any such adjustment, the current may be increased or decreased by the rheostats 50 or 52.

The windings 41-42 are of polarity suitable for the generator 33 and the motor 34 respectively.

The operation of the power unit A will be described later.

At E is a differential gearing comprising a spider element 53, rotatably supporting pinions 54-54, meshed with differential gears 55-56; the strip driven shaft 12 being connected to the gear 55.

At G is indicated generally a speed reference unit comprising a differential gearing F and a variable speed ratio transmission H.

The gearing F comprises a spider element 57 rotatably supporting pinions 58-58 meshed with differential gears 95-60. A chain sprocket wheel 61 is connected to the gear 60. A shaft 62 connects the gear 59 with the aforesaid gear 56. The spider element 57 is connected to a shaft 63 extending therefrom through an axial opening 64 in the gear and sprocket wheel 61. I 1

The shaft 63 is a power input shaft driven by a motor 65 through gears 66-67, and is a part of the variable speed ratio unit H as follows.

The shaft 63 has splined thereon an expansible an contractible pulley 68. A shaft 69, hasan expansible and contractible pulley 70 splined thereon, and has a sprocket wheel 71 connected thereto; and a sprocket chain 72 connects the two sprocket wheels '7 1-61. The pulleys 68-70 are connected by a be1t.73.

A pair of rocking levers 74-75 are pivoted at 7 6-77 and at opposite portions engage opposite sides of the pulleys 70-68. The levers extend beyond the pulley 68 and at their ends engage nuts 77-78 threaded on a screw 79 having right and left threads 80-81.

Upon rotation of the screw 79 the nuts 77-78 are propelled oppositely along the screw, and rock the lovers 7475 oppositely on their pivots 76-77, and thereby operate the pulleys 68-70 to expand the diameter of one and contract that of the other to vary the speed ratio of transmission therebetween by the belt 73.

The variable speed ratio transmission H here described, will be recognized as one of the Reeves type; but such a transmission has been chosen for illustrative purposes only; and as such is not an essential part of the invention; and it Will be understood that any other type of variable speed ratio transmission may be used with which. the aforesaid mechanical connections to the differential gearing E can be made and which has a rotary adjusting element corresponding to the screw 79.

The screw '79 is turned in alternate directions by a reversible adjusting motor 82, connected to the screw through gears 83-84.

The motor 82 is preferably a squirrelcage induction motor, and is connected by wires 85-86-87 to alternating current mains 88-39-99 through normally open, forward and reverse push button contactors 91 92.

Upon momentarily closing one or the other of the contactors, 91 or 92, the motor 82 will momentarily turn the screw 79 in a corresponding direction; the reversing connections illustrated being conventional and not needing description in detail. I

A shaft 93 is connected at one'end to a rotary contact 94 of the rheostat 50, and at the other end is connected to the screw 79, through a gear 95 on the shaft meshed with a gear 96 on the screw 79; whereby adjustment of the screw by rotating it as aforesaid, concurrently rotates the contact 94, for a purpose to be described.

At I generally is shown a mechanism for braking rotation of the wound drum 1, as strip 4 is unwound therefrom, whereby torque applied to the winding drum 11 by the power unit A, develops tension in the strip.

The braking mechanism comprises two differential gearings K and L; the differential gearing K comprising a spider element 99 rotatably supporting pinions 100-100 with differential gears 101-102, and the differential gearing L comprising a spider element 103 rotatably supporting pinions 104-104 meshed with differential gears 105106.

The spider elements 99 and 103 have peripheral teeth meshed together at 107.

The differential gears 101 and 105 are connected respectively to gears 108-109, both meshed with an intermediate gear 110, to which the shaft 2 is connected.

The differential gears 102 and 106 are connected respectively to units 111 and 112, constructed like direct current generators or motors and at this point the unit 111 will be considered as a generator, and the unit 112 as a motor. The generator 111 has a closed series load circuit comprising wires 113-114. The generator 111 may generate current in the load circuit, which as shown,'includes the motor 112 in series, and thereby may drive the motor 112; or, as will appear later there may be times when the motor 112 may act as a generator and drive the unit 111 as a motor.

The generator and motor, 111-112 have shunt field windings 116-115 respectively, energized from D. C. main 117-118 through a rheostat 119, comprising a resistor 120 and a rotary contact 121. Current from the main 117 goes to the contact 121 and there divides, part going through part of the resistor 120 to the field winding 115 and thence to the main 118, and part going through the other part of the resistor 120 to the field winding 116 and thence by wire 122 to the main 118.

The rotary contact 121 is connected to the spider 53 of the differential gearing E, the spider having peripheral teeth meshed with a gear 123, which, through gearing 124-125 is connected by a shaft 126 to the rotary contact 121.

Operation of the various parts above described will now be explained.

In general, the power unit A, applies torque from the motor 15 to the winding drum 11 to wind strip 4 in a coil 10 thereon; and the brake mechanism I brakes rotation of the unwinding drum 1, whereby the power unit A develops tension in the strip.

The braking action varies, as will be described, in correspondence with any tendency of the strip speed to vary, by response of the mechanism E to strip speed, whereby the strip speed is maintained constant.

With constant strip speed thus produced, then as winding goes on and the diameter of the coil 10 correspondingly increases, the torque applied to the drum 11 by the power unit A automatically increases by inherent action of the power unit A, to keep the strip tension constant at that speed.

A power unit such as that shown generally at A, constitutes part of the subject matter of a copending patent application of Lev A. Trofimov, filed May 31, 1949, Serial Number 96,372 new Patent 2,648,502 of August 11, 1953 to which reference may be had for a more detailed description; and the operation of the unit A will therefore be more briefly described herein as follows.

At the unit A, the power motor 15 runs continuously, at substantially constant speed, and by gear 29 drives the spider 20. For purposes of explanation, if it be assumed that the output shaft 14 and gear 28 are held at rest, and gears 25-27 accordingly at rest, the gear 23 and the generator 33 connected to it would be driven at twice the speed of the spider 20, which is the maximum possible speed for the generator.

The power supplying motor 15, by means of gears 32 and 31, also drive the differential gear 19; and if again it be assumed that the output shaft 14 is held at rest, and that gears 25-18 are correspondingly at rest, the motor 34 connected to the spider 16 would be mechanically driven by it in the same direction as the generator 33 and at one half the speed of the gears 31-19, which is the minimum possible speed for the motor 34.

The spider 20 and gear 31-19 are both constrained to rotate at constant fixed speeds by being geared to the power motor drive shaft 30.

The generator 33 thus driven, generates load current in the load circuit 37-38, and therefore torque is required to drive it, and this torque, is drawn from the spider 20 through gear 23, and an equal torque accordingly appears at the gear 22 and is applied to the gear 27.

The gear 27 applies the torque to the gear 28 and output shaft 14 in the winding direction.

Assuming now that the drum ll be allowed to turn, the gears 27-22 will rotate and accordingly gear 23 and generator 33 will slow down and run at reduced speed, less than said maximum speed.

Also, the generator current flows in the motor 34 tend ing to drive it electrically in its mechanically driven direction, and it develops motor torque, which it applies to the spider 16, and the spider, reacting on the gear 19, applies torque to the gear 18 and thence through gear 25 to the gear 28 and output shaft 14, to drive the drum 11 in the winding direction.

Also gears 25 and 18 now rotate and accordingly the spider 16 and motor 34 speed up and run at a higher speed than said minimum speed.

Torques from both the generator 33 and motor 34 now jointly drive the drum 11 in the winding direction. The brake mechanism, shown generally at I and to be described, brakes the movement of the strip 4 as referred to and accordingly the rotation of the drum 11 develops tension in the strip 4.

At the beginning of winding, the coil 10 is of small diameter; and the values of the generator and motor torques are at that time adjusted, by manually operating the rheostats 48-46 to adjust the current in the field windings 41-42, until the joint torque on the drum 11 produces the desired tension in the strip 4 at the linear speed at which it is moving.

As will be explained, the strip speed may be selectively predetermined and set, and when once set is maintained constant at that selected value.

As winding goes on, the diameter of the coil 10 increases. To maintain constant the said desired tension in the strip, the joint generator and motor torque applied to the drum, must therefore gradually increase, and this is effected by the power unit A by automatic inherent action as follows.

For any speed of the generator 33, it generates a corresponding current in the load circuit 37-38; and a corresponding drum driving joint torque is developed. Upon an increase of coil diameter, for the strip speed and tension obtaining at the time, this torque becomes insufiicient to maintain the speed of the drum 11 and it tends to slow down, slowing down gear 28.

Slowing down of gear 28, causes gear 22 to go slower and this causes gear 23 and the generator 33 to be driven faster by differential gearing action; and the generator generates more current in the load circuit 37-38. This increased current develops increased driving torque taken by the generator and correspondingly increases the torque at gear 27 applied to the drum.

Slowing down of gear 28 also causes gear 18 to vgo slower and this causes the spider 16 and motor 34 to go slower. The current generated in the load circuit is proportional to the difference between the voltage of the generator and'the counter voltage of the motor; and the latter falls as the speed of the motor decreases; so

that slowing down of the motor also causes the current to increase.

The motor 34 develops increased torque due to the increased load current going to it, and its increased torque is also applied to the drum by the gear as will be understood.

The drum of course must rotate at reduced speed as the coil diameter increases, if as desired, the strip speed and tension are to be held constant; but the torque applied to it must be increased, because of the increased diameter. And by the foregoing inherent automatic action, as the drum requires more driving torque and slows down, a corresponding increase of generator load current occurs; and the increased load current by increasing the torque developed by the generator 33 at the gear 27 and also by the motor 34 at the gear 25, raises the joint torque applied to the drum at its reduced speed.

Thus the torque-speed characteristic of the power unit A at its output sha t is, that as its speed decreases the torque applied to it automatically rises, and vice versa.

In general it has been found in practice, that the generator load current will tend to increase as aforesaid, at a rate to substantially exactly compensate for the increase of joint torque required on the drum to maintain the strip tension constant. Any deviation from exact compensation is in the direction of too great an increase of generator current. Accordingly, the series field 35 is in some cases provided, and operates as follows.

The value of generator current at all times is determined primarily by the strength of the shunt field due to the winding 41.

The series field winding 35 is wound in the direction to weaken the generator field produced by the field winding 41; and the effectiveness of the series winding 35 is adjustable by the rheostat 39, which diverts more or less of the load current from the winding 35.

Thus an exact compensating correspondence of the aforesaid generator current increase and the increase of driving torque requirement of the drum, for constant strip tension, may be effected by a fixed adjustment of the current in the series field winding 35 by the rheostat 39. v

This correspondence of current increase and applied drum torque increase, can, alternatively, be effected at the motor 34 instead of at the generator 33, by the series field winding 36, and the rheostat the winding 36 in this case assisting the field winding 42, causing the counter voltage of the motor to be greater.

Inherent regulation of the power unit A to vary the drum-applied torque as described to maintain constant tension in the strip 4, contemplates constant linear speed of the strip and this is effected by the braking mechanism I under joint control of the gearing E and the speed reference unit G, which will now be described.

In general unwinding of the strip 4 from the drum 1, rotates it and its shaft 2, and by means of the gearings K-L, the power supplying motor 97 is driven as a generator and supplies power back to the mains 98, and a hold-back load torque or braking action is thereby effected on the shaft 2 and drum 1.

The generator 97 has the construction of a squirrel cage induction motor which could be driven as a motor by alternating current from the mains 98-98; but as is well known when such a motor is mechanically driven above synchronous speed, the curve of torque to drive it rises very steeply, very much the same as the output torque curve rises when it delivers power as a squirrel cage motor and is mechanically loaded to reduce its speed below synchronous speed.

Other types of electric generators, D. C. or A. C. may be employed as the generator 97 but a squirrel cage induction motor type is preferred because of its simplicity and its rapidly rising torque as aforesaid when driven as a generator.

For purposes of explanation it will first be assumed that the fields of the units 111-112 are equally energized by their field windings 116-115 by some midposition of the rheostat contact 121; and the drum 1 and shaft 2 are at rest; and that the unit 97 is connected to the mains 98-98 and runs as a motor and drives the two spiders 103-99 in opposite directions.

Torque from the spider 99, under these assumed conditions, divides equally between differential gears 101 and 102; and torque from the spider 103 likewise divides equally between differential gears 105-106.

This tends to drive the connected pairs of gears 101- 108 and 105-109 in opposite directions the same as the spiders 99-103, but the gears 108-109 being both meshed with the gear 110, no rotation occurs; and the units 111-112 are driven in opposite directions, and at twice the speed of the spiders, 103-99.

The units 111-112 having equal fields, under these assumed conditions, their output potentials are equal and opposite, and no load current flows in the load circuit 113-114 and no torque is developed at the units 111- 112.

All torques in the transmission, under these assumed conditions, are negligibly small, and the motor 97 will run at substantially synchronous speed.

if now the rheostat contact 121 be moved counterclockwise as viewed in Fig. l, to a position at the left of said midposition, at which the field winding 115 of unit 112 will be energized more strongly than the winding 116 of unit 111, the unit 112 will act as a generator and generate current in the circuit 113-114 and drive the unit 111 as a motor.

Torque is required to drive the loaded generator 112 and is taken from the power driven spider 103 driving the gear 106, and an equal torque consequently is developed on the gear 105 and its connected gear 109, the latter applying its torque to the gear 110, shaft 2, and roll 1, and in the direction to drive the roll in the forward or unwinding direction, or clockwise as viewed in Fig. l.

The generated load current going to the motor 111 drives it as a motor and its developed torque on the gear 102 reacts on the spider 99 and develops an equal torque on the gear 101 and its connected gear 108, the latter applying its torque to the gear 110, and shaft 2 in the direction to also drive the roll 1 in the forward or clockwise direction of Fig. 1.

This forward drive of the roll 1 results as aforesaid from a position for the contact 121 counterclockwise from its midposition; and the contact 121 will be moved to this position as soon as the apparatus is started up because until the roll 1 begins to rotate clockwise the speed-set gear 56 of gearing E will rotate faster than gear 55; and the action of the spider 53 of the gearing E will rotate the contact 121 counterclockwise as will be understood from the description hereinbefore.

This counterclockwise rotation of the contact 121 effects more and more driving torque on the roll 1 and coil 3 and the latter rapidly speeds up toward a speed for the strip, at which the speeds of the gears 55 and 56 of gearing B would become equal, and the contact 121 would stop moving counterclockwise.

If the contact 121 were to come to a position corresponding to which the roll 1 and coil 3 and strip 4 being wound on the roll 11 would go so fast that the gear 55 at the gearing E (whose speed is controlled by the strip speed) would go faster than the gear 56, the spider 53 would reverse and move the contact 121 clockwise and reduce the forward driving torque on the roll and the power driven speed of the roll.

The contact 121 thus tends to come to the mid position at which no driving power would be applied to the roll 1, but does not actually do so because the power unit A winding the strip on the roll 11 constantly tends to cause the gear 55 to go faster than the gear 56 and the contact 112 therefore will always come to a counterclockwise 9 position, corresponding to a forward power driven speed for the roll 1, .at which the tangential speed or strip speed therefrom, is less than the speed of the strip being Wound on the roll 11. The striptherefore overhauls the roll 1 and the roll 1 is strip-driven faster than it tends to be power-driven. This causes the mechanism I to exert braking action on the strip and causes tension to be developed in it as follows.

Overhauling the roll 1 and increasing its speed above that produced by the power supplying motor 97, causes the gears 108-101 and the gears 109-105 to be driven in the same direction by the gear .110. The spider 99 is driven oppositely to the spider 103. The spider 103 is driven in the same direction as the gears 108-101 and the spider 99 oppositely to the gears 108-101. Thus the gear 102 and unit 111 will be driven in the same direction as the spider 99.

Thus the spider 99 and the unit 111 will be driven in the same direction, and the unit 1'11 will act as a generator and drive the unit 112 as a motor.

Torque to drive the generator 111 comes from the gears 108-110 and is supplied by the overhauling roll 1 and tends to retard it, exerting a braking action thereon.

The motor 112 applies torque to the gear 106 to drive it. The gears 109-105 are being driven by the overhauling roll 1. Both gears 106 and 105 therefore react on the spider 103 to over-drive it in the same direction it is being driven, and this drives the motor 97 above synchronism and it becomes a generator supplying current back into the line 98. The torque to thus over-drive the motor 97 comes from the motor 112 and from the gear 109, and the torque of the latter comes from the roll 1 and tends to retard it and also exerts a braking action thereon.

Braking action by the unit I as a whole is thus developed by power driving the roll 1 at a relatively low speed but overhauling by the strip at a higher speed, against the opposition of the transmission and against the driving of the power motor 97 as a generator.

As aforesaid, upon starting up the apparatus, the coil is power-driven to accelerate it and bring it up to the speed of operation. This is one of the particular advantages of the invention in another aspect.

In some cases, the roll 1 and the coil 3 thereon may be of very great weight and inertia; and it would be undesirable to subject the strip to the tension that would be produced thereon by the winding unit A to start and accelerate the roll 1. By the operation above described in connection with the braking action of the unit I, the roll 1 is power driven to start and accelerate it, the greater its inertia, and the more slowly it tends to accelerate, the greater the accelerating power applied to it.

The braking action of the mechanism I is controlled to vary with variations of strip speed to maintain the strip speed constant, by the speed responsive gearing E and the speed reference mechanism G.

The speed reference mechanism G will be set for a desired strip speed, by momentarily closing one or the other of the push button contactors 91 or 92, to momentarily operate the motor 82 in forward or reverse direction, to turn the screw 79 correspondingly; and, by levers 74--75 will determine relative diameters for the belt pulleys 70-68.

The continuously running motor 65 rotates the shaft .63 and differential spider 57; and by the belt pulleys and belt 73, rotates the sprocket 71, and by sprocket chain 72, rotates the differential gear 60. The spider 57 reacting on the gear 60 drives the gear 59 and the gear 56 connected to it.

A very wide range of speeds may be had for the gear 56 by this arrangement, from zero speed to a high maximum speed with a relatively low speed ratio of diameters for the pulleys 70-68 such as 4 to 1.

It is therefore the speed of the gear 56 in gearing E that is adjusted and fixed for speed reference purposes.

The gear 55 of gearing E is driven at a speed corresponding to the strip speed, by the shaft 12 connected to roll 9 which grips the strip 4 and is rotated by it.

So long as the strip is moving at the desired preset speed, the gears 55 and 56 will rotate at the same speed and in opposite directions, and the spider 53 will remain at rest. Upon a change of strip speed, say a speed increase due to any cause, the gear 55 will rotate faster than the gear 56 and this will rotate the spider 53, and through gears 123-124 and 125 the shaft 126 will be rotated and rotate the contact 121 of the rheostat 119 clockwise and increase the field strength of the generator 111 and weaken that of the motor 112 which as described above will increase the braking action on the strip, by increasing the torque applied to oppose rotation of the roll 1 and restore it to its original speed at which the gears 55 and 56 will again rotate at the same speed any further increase of braking action will cease. The same action acting reversely will decrease the braking effect if the strip speed should decrease.

Thus the strip speed is held constant; and its speed being constant, the tension therein is maintained constant as described by the inherent action of the power unit A.

In the same manner, the braking action may be adjustably varied to bring the strip to a new desired speed when as described the unit G is adjusted to that new speed, explained as follows.

The power unit A, as described, develops increased torque on the winding drum, if the drum tends to slow down due to increasing coil diameter, and thus maintains the strip tension constant at a constant strip speed.

Conversely, the unit A will develop decreased torque if the winding drum were to tend to speed up.

If, as above mentioned, the speed of the strip be increased intentionally by adjustment of the unit G, the winding drum would tend to increase in speed and the unit A would develop less driving torque; and at the new strip speed the tension would be maintained by the unit A at a decreased value.

It is desirable however to be able to adjust the strip speed as described, without having the strip tension change as here referred to. This is provided as follows.

The joint torque applied to the drum 11 by the generator 33 and motor 34, is predetermined as described by manual adjustment of the rheostats 48 and 46 to adjust the strength of current in the field windings 41-42.

After being once determined in this manner, if the energization of both fields be changed proportionally at the same time, for example if the generator and motor fields be strengthened, the predetermined applied torque will increase.

When therefore, as aforesaid, the strip speed is increased by adjustment as described, and the strip tension tends to decrease, this change of tension would be compensated for and the tension restored again to its original value by manually operating the rheostat 50, in series with the current supply to the field windings 41-42, to increase their energizations.

However, it is preferred to elfect this compensation automatically so that when the strip speed is changed the tension will remain the same.

This is done by the described interconnection between the screw 79 and the rotary contact 94 of the rheostat 50, comprising the gears 95-96 and the shaft 93. When the screw 79 is turned to adjust the strip speed as described, the contact 94 is also rotated to effect the said compensation.

Having nce ascertained the amount of movement of the contact 94 to compensate for a change of speed effected by a given amount of rotation of the screw 79, a suitable resistance per unit length of the resistor 50A and a suitable ratio for gears 96-95 is readily determined, which will operate the rheostat 50 upon a change of selected strip speed by the unit G to maintain the strip tension constant as referred to.

In practice, it is also desirable to be able to change the strip tension without changing the speed thereof. This is done by manual adjustment of the rheostat 52, which as will be understood in view of the foregoing will change the strength of the fields of both the generator 33 and motor 34 and change the drum applied torque and the strip tension, the change of torque not changing the strip speed because that is maintained constant by the apparatus at E and I.

Thus in general, the braking mechanism I brakes linear movement of the strip 4, and the power unit A applies torque to the winding drum 11 to wind the strip and develop tension in it. The speed of the strip can be preset by adjusting the speed reference mechanism G, and once set, the braking mechanism 1, responding jointly to the mechanisms G and B, will maintain the speed constant. For constant strip speed thus maintained, the power unit A automatically and inherently modifies the torque it applies to the winding drum 11 to maintain the strip tension constant, as winding goes on and the diameter of the coil 11.5 on the drum 11 increases. The amount of torque applied to the drum 11 and accordingly the strip tension at any strip speed is determined by adjustment of the rheostat 52 and may thereby be selected. Upon a change of selected strip speed, the rheostat 50 is automatically operated to compensate for the change of strip tension that tends to occur to maintain the tension unchanged at the changed speed. Thus the strip speed and strip tension can both be adjustably changed to desired values, and either can be changed without changing the other.

There are uses for the apparatus as above described in which the power to turn the rolls -7-9 is small and may be disregarded; but in some installations it may be great enough to affect the strip tension.

In Fig. 1, the strip tension is in general selectively adjusted at the power unit A as described. This tension deevlops in the strip at the right side of the rolls 5-7-9. If considerable power is absorbed by the rolls, and considerable torque must be accordingly applied to them by the strip to locate them, the tension in the strip at the left of the rolls may be less than that at right, and less than is wanted.

Again, in some cases, the torque to drive the rolls may be so great that more tension must be developed in the strip at the right of the rolls than is wanted; or it may even be greater than the material of the strip can sustain.

it is therefore desirable in some cases to compensate for the power and torque required by the rolls 5-7-9 and this is done as shown in Fig. 2, by a power unit shown generally at M, which applies supplemental torque to the shaft 12 and roll 9; and as will be described, the applied torque may be adjusted to any amount desired, and will thereafter automatically be maintained constant, regardless of changes of speed of the roll 9, as the speed of the strip is adjustably varied. The supplemental torque as will be understood takes tension load from the strip at the right side of the rolls, to any desired degree and for any purpose.

The mechanism M comprises two differential gearings N and O.

The gearing N comprises a spider element 127 rotatably supporting pinions 128-128 meshed with differential gears 129-139.

The gearing 0 comprises a spider 131 rotatably supporting pinions 132-132 meshed with differential gears 133-134.

The differential gears 129-133 are connected respectively to gears 135-136 meshed with an intermediate gear 137; and the gear 137 is connected to a gear 138 meshed with a gear 139 on the shaft 12.

The differential gears 134-139 are connected respectively to a generator 140 and a motor 141 preferably of D. C. type and they are provided respectively with field windings 142-143 energized from direct current mains 144-145, through a common rheostat 146 having a resistor 147 and a rotary contact 148.

Current to the field windings goes from main 144 through part of resistor 147, contact 148, and then divides, going respectively through the windings, 142-143 to the main and the current in the field winding 143 goes through part of the resistor 149 of a rheostat 150 having a movable contact 151 whereby the current in the winding 143 may be independently adjusted.

The generator 140 has a series field winding 152 which when energized, as will be described, opposes the energization of the winding 142. I

The spiders 127-131 have peripheral teeth meshed together as at 153. A power supplying motor 154 drives a pinion 155 meshed with the spider 127 and thus drives both spiders 127-131 and in opposite directions.

The generator 140 has a local closed load circuit comprising, as shown, the series field 152, the motor 141 and a wire 156.

For purposes of explanation it will at first be assumed, that the shaft 12 and therefore gears 138-139 are at rest. Torque from the spider 127 divides equally between differential gears 129-130; and torque from the spider 131 divides equally between differential gears 133-134. If the generator and motor fields were not energized, the generator 140 and motor- 141 would be mechanically driven by the gears 134-130 in opposite directions and each at twice the speed of the spiders 131-127, because the gears 136 and 135 while tending to be driven in opposite directions, remain at rest, being both meshed with the gear 137; and under these assumed idling conditions, all torques developed would be negilgibly small.

With the windings 142-143 energized however, and assuming that the generator field is more strongly energized than the motor field, the generator 140 generates current in its said local load circuit and the current drives the motor 141 in the same direction as under said idling conditions.

It requires torque to drive the loaded generator and this torque is drawn from the spider 131 through gear 134; and an equal torque is applied to the gears 133-136 in the same direction as during said idling conditions.

The driven motor 140 now electrically driven, develops torque and applies it on the gear 130, and the latter reacting on the spider 127 applies a like torque to the gears 129-135 in the direction opposite to that of the said idling conditions.

The gears 136 and 135 are now applying their torques in the same direction on the gears 137-138 tending to drive them.

On the said assumption that gears 137-138 were at rest, the generator 140 and motor 141'were being driven both at the same speed.

Under conditions of practice, however, the shaft 12 and gears 139 and 138 are driven by the roll 9 as described, and gear 137 will therefore rotate and while rotating, the sum of the torques from gears 136 and 135 are applied thereto in the rotating direction; and whatever this torque is, as will appear later, it is applied to the roll 9 through the gears 138-139 and shaft 12 in its rotating direction.

Due to rotation of gear 137, generator 140 and motor 141 no longer run at equal speeds the generator running slower and the motor running faster, due to the mechanical interconnections of the gearing, it being a fact that, with two differential gearings in this arrangement, the sum of the speeds of the motor and generator is constant at all speeds. The actual speeds of the generator and motor are fixed for any constant strip speed and corresponding constant speed of the shaft 12 and gear 137 as will be understood.

The torque thus produced on the gear 137 and transmitted to the roll 9, comes from both the generator 140 and the motor 141. The value of the torque in each case depends upon the field strength and the value of adjustable at the rheostat 156; the strength of both fields is concurrently adjustable at the rheosta-t 146. The strength of the generator field is also controlled by the series field winding 152, neutralizing part of the field produced by the winding 142.

These particular provisions for field energizat ion, as illustrated and described, are predicated on the particular requirements of the winding apparatus, as follows:

The speed of the strip 4 can be adjusted to different values from time to time, as described, and the speed of the roll 9 will therefore correspondingly change from time to time.

It is a simple matter to make the mechanism M which applies supplemental torque to the roll 9, so that it will be adjustable, to adjust the applied torque to a selected value at any one given speed of the roll 9, and thereafter to maintain the applied torque constant at that selected value at that speed. But the problem arises of causing the mechanism M to maintain the selected applied torque value without change, when the speed of the strip and roll 9 are adjustably changed. This problem is solved by the said field energizing arrangement, explained as follows.

The torque on the gear 137 from the motor and from the generator, as described, is proportional to the product of their respective field strengths and the current in the generator local circuit.

The current in the local circuit will be proportional to n the difference between the generator voltage and the' back voltage of the motor. These respe'etive 'voltages will he determined by the respective field strengths of the generator and motor, and by their respective speeds.

For some intermediate setting of the rheostat 146, the generator field winding 142 is strongly energized and gives it a strong field; and the motor field winding 143 is adjusted to relatively weak energization by the rheostat 150, giving it a weak field; and for any adjusted strip speed, the gear 137 has a corresponding speed and the generator 146 has a corresponding relatively low speed and the motor 141 a relatively high speed.

The currents in the field windings are therefore adjusted, to adjust the current in the local circuit, in correspondence with the speeds of the generator and motor at the time (determined by the speed of the roll 9 and gear 137 at the time) so that the joint torque of the generator and motor applied to the gear 37 and roll 9 will have the desired selected value.

The generator series field winding 152 opposes the field winding 142, and the adjustment of the current in the generator field winding 142 will accordingly have a somewhat higher value than otherwise.

If now the speed of the strip be changed, say increased, the speed of gear 1.37 will correspondingly increase (being connected to the roll 9). This will cause the speed of the generator 140 to decrease and similarly cause the speed of motor 141 to increase, as aforesaid.

The generator then will generate reduced current, due to lower speed and corresponding lower voltage, and to increased counter voltage of the motor. The field strength of the generator will increase due to less neutralization by its series winding 152.

The torque from the motor will be somewhat decreased (constant field and reduced current) but the torque from the generator will be increased (reduced current but increased field).

By suitably predetermining the ratio of the series field winding to the generator separately excited field winding, and suitable initial adjusted values of the field energizations, the decreased motor torque can be exactly compensated for by the increased generator torque. To this end the etfectiveness of the series field may be made adjustable by a rheostat such as is shown in Fig. 1 at 39.

The reverse of this action occurs if the speed of the strip and gear 137 is decreased instead of increased.

In this manner the supple nental torque applied to the roll 9 by the mechanism M remains constant at a preset value at all speeds of the strip.

In Fig. 2, the shaft 12 is shown as going to the gear 55 of gearing E, described for Fig. 1 and the shafts 14 and 2 as going to the mechanisms A and 1 respectively of Fig. 1, as indicating that these mechanisms, not shown in Fig. 2, are a part of the arrangement of Fig. 2. The rotation of shaft 12 by the strip 4 through the agency of the roll 9, and the operations effected thereby are unchanged and not interfered with by the supplemental torque applied to the shaft 12 by the mechanism M.

The braking mechanism shown at I in Fig. 1 is the type preferred; but in some cases, a friction type brake mechanism may be utilized, as shown in Fig. 3 at P.

The shaft 2 of the unwinding drum 1 has a brake drum 1577 thereon. A brake shoe 158 is held against the drum by a spring 159 with variable pressure by an arm 160, pivoted at 161 and engaged by a cam 162. Rotation of the cam in one direction or the other causes the arm to rock in one direction or the other to vary the braking effect.

The cam is on a shaft 163 connected by gears 164 to 166 to the spider 53 of the gearing E reproduced from Fig. l.

A brief description of operation will suffice. The gears '59 and '56 are driven by the speed reference unit G of Fig. '1. Any difference between the speed of the gear 56, and the gear 55 driven by the strip 4 through shaft 12, causes the spider '53 to rotate and rotate the cam 162 to correspondingly change the braking effect of the brake shoe 158 on brake drum 157; for the same end results described in full for the braking mechanism I of Fig. '1.

In the foregoing, the strip 4 has been described as being unwound from a supply coil on a drum 1 and wound on a drum 11.

There are instances wherein it would be desirable to practice the invention by winding strip material coming from a supply source other than a wound drum, and to exert braking action thereon, for the purposes of the invention.

In Fig. 4 is illustrated fragmentarily one such modification.

The strip, as at 4A, comes from any supply source; and on its way to the above described tier of rolls 579, is gripped by a similar or like tier of rolls 167168169. The strip is drawn through the rolls as it is wound on the drum 11 by the power unit A of Fig. 1 and drives the roll 169 in the same manner as it does the roll 9 of Fig. 1.

The shaft 2 is connected at one end to the roll 169 and at the other end is connected to a braking mechanism such as I, Fig. l, or P, Fig. 3, as described for the shaft 2 of these figures.

The shaft 12, driven by the roll 9 is connected through the gear 55 to the parts described for Fig. l.

Braking action is thus exerted on the shaft 2 and roll 169 and therefore on the strip 4 for the purposes described for Fig. 1.

It will be understood that supplemental torque may be applied to the roll 169 for any purpose if desired, as described for the application of supplemental torque to the roll 9.

As to the power supplying motors 15, 65 and 97 of Fig. 1; and the motor 154 of Fig. 2 when the supplemental torque mechanism M is to be used; they will in general be started and brought up to full speed all at the same time in which event the respective supply wires to the motors may all be connected to a common current supply through a well known common motor starting contactor or apparatus, not shown.

However, the motors have been shown as having sep- 15 arate supply conductors as indicating that starting contactors or other starting apparatus may be provided, individually for each motor and the motors therefore started and brought up to speed at different times-if desired.

Subject matter described herein but not claimed is being claimed in my copending application Serial No. 258,904, filed November 29, 1951, for Strip Material Winding Apparatus now Patent 2,639,868 of May 26, 1953.

I claim:

1. In a strip winding apparatus, a power driven strip winding drum, a first rotary element arranged to be rotated by the strip as it is being Wound, braking mechanism braking rotary movement of the first rotary element whereby the winding drum develops tension in the strip, a second rotary element between the first rotary element and the winding drum, said second rotary element being driven by the strip, means driven by the second rotary element controlling the braking action to effect increase or decrease thereof upon tendency of the strip speed to increase or decrease, and power operated means applying supplemental torque to the second rotary element in its strip driven direction.

2. In a strip winding apparatus, a power driven strip winding drum, a first rotary element arranged to be rotated by the strip as it is being wound, braking mechanism braking rotary movement of the first rotary element whereby the winding drum develops tension in the strip, a second rotary element between the first rotary element and the winding drum, said second rotary element being driven by the strip, means driven by the second rotary element controlling the braking action to effect increase or decrease thereof upon tendency of the strip speed to increase or decrease, and power operated means applying supplemental torque to the second I- 15 tary element in its strip driven direction, said power operated means being adjustable to adjustably select the value of the supplemental torque.

3. In a strip winding apparatus, a power driven strip winding drum, a first rotary element arranged to be rotated by the strip as it is being Wound, braking mechanism braking rotary movement of the first rotary element whereby the winding drum develops tension in the strip, a second rotary element between the first rotary element and the winding drum, said second rotary element being driven by the strip, means driven by the second rotary element controlling the braking action to efiect increase or decrease thereof upon tendency of the strip speed to increase or decrease, a power driven transmission applying supplemental torque to the second rotary element in its strip driven direction, the transmission being adjustable to adjustably select the value of the supplemental torque, means to adjustably change the speed of the strip toward the winding drum, and correspondingly changing the speed of the second rotary element, and the transmission comprising means responsive to changes of speed of the second rotary element to maintain substantially constant the selected value of supplemental torque through a rangeof speeds of the rotary element.

References Cited in the file of this patent UNITED STATES PATENTS 1,881,056 McBain Oct. 4, 1932 2,157,267 Madle May 9, 1939 2,590,682 Cawley et a1. Mar. 25, 1952 2,590,491 Bendz Mar. 25, 1952 2,639,868 Trofimov May 26, 1953 2,648,502 Trofimov Aug. 11, 1953 

